DP980冷轧高强钢连续退火工艺及强韧性行为研究

采用连续退火模拟试验机研究了连续退火工艺中缓冷及过时效温度对DP980冷轧高强钢组织性能的影响规律,并利用扫描电镜、透射电镜及拉伸试验机进行了显微组织及力学性能检测。研究结果表明：缓冷温度降低有利于新生铁素体及富碳岛状马氏体的生成,且实验钢屈服强度基本不变,抗拉强度先下降后升高,伸长率逐渐上升。缓冷温度为650 ℃时,强塑积（PSE）达到最大值15.55 GPa·%。随着过时效温度的升高,实验钢抗拉强度及屈服强度略有下降,断后伸长率显著升高。工业试制HC550/980DP成品的屈服强度不小于570 MPa,抗拉强度不小于1 080 MPa,伸长率不小于7%,达到应用标准。     

Effect of Y content on microstructure and mechanical properties of 2519 aluminum alloy

The effects of yttrium（Y） content on precipitation hardening, elevated temperature mechanical properties and morphologies of 2519 aluminum alloy were investigated by means of microhardness test, tensile test, optical microscopy（OM）, transmission electron microscopy（TEM） and scanning electron microscopy（SEM）. The results show that the tensile strength increases from 485 MPa to 490 MPa by increasing Y content from 0 to 0.10%（mass fraction） at room temperature, and from 155 MPa to 205 MPa by increasing Y content from 0 to 0.20% at 300 ~C. The high strength of 2519 aluminum alloy is attributed to the high density of fine 0＇ precipitates and intermetallic compound AICuY with high thermal stability. Addition of Y above 0.20% in 2519 aluminum alloy may induce the decrease in the tensile strength both at room temperature （20 ℃） and 300℃.     

960 MPa级高强钢相变规律及热处理工艺探讨

借助DIL805A/D淬火变形膨胀仪,通过金相、透射电镜、室温拉伸、-40 ℃冲击测试等分析手段,研究了热处理工艺对960 MPa级高强钢组织与性能的影响。结果表明：在790～880 ℃温度范围内,试验钢随着淬火加热温度的提高,马氏体量逐渐增加,铁素体量逐渐减少,在850 ℃淬火,铁素体含量基本为零,组织最为均匀细小。随着回火温度从180 ℃提高到450 ℃,马氏体的板条逐渐分解,板条状的渗碳体开始聚集和球化。淬火加热温度高于850 ℃时,材料的屈服强度大于960 MPa;在450 ℃回火,材料具有更佳的冲击韧性。对本试验钢而言,采用850 ℃淬火+450 ℃回火,具有最佳的强韧性匹配。     

时效工艺对纳米结构2297铝锂合金力学性能与微观组织的影响

采用535 ℃×2 h固溶制度,将热锻态2297铝锂合金固溶水淬后冷轧,冷轧压下量为95%,然后将轧制样品在不同温度(120~190 ℃)和时间(0~80 h)范围内进行时效处理。采用拉伸、扫描电镜(SEM)和透射电镜(TEM)等测试方法,分析时效温度和时间对铝锂合金组织与性能的影响。结果表明:时效前的大塑性变形能获得纳米结构组织,能促进T₁相均匀细小地析出,缩短合金达到峰时效的时间,最终成功制备了高强高塑性铝锂合金。在120~140 ℃温区内时效时,时效温度越高,达到峰时效的时间越短、强度越高。140 ℃达到峰时效时间缩短为40 h,此时合金的抗拉强度、屈服强度和伸长率分别为525 MPa、478 MPa和7.7%,主要强化相为细小的T₁相。在170~190 ℃温区内时效时,时效温度越高,达到峰时效的时间越短,但抗拉强度与屈服强度迅速下降。170 ℃时效8 h达到峰时效状态,此时合金的抗拉强度、屈服强度和伸长率分别是503 MPa、462 MPa和5.0%,主要强化相仍为T₁相,但已经明显粗化。     

化学镀镍层与Si3N4陶瓷的界面反应

采用真空加热和辉光离子轰击加热两种方式,对化学镀镍Si3N4陶瓷进行扩散热处理,并利用X射线衍射仪分析和讨论了化学镀Ni层与Si3N4的界面反应.分析表明,辉光离子轰击扩散能够显著促进镀Ni层与Si3N4的界面反应,其界面反应产物为Ni2Si、Ni3Si和Ni5Si2.随着扩散热处理温度的提高,反应产物的数量明显增加.处理前后,化学镀镍Si3N4陶瓷与金属钎焊接头剪切强度可由70mPa提高至123mPa.     

Tensile Behavior of SiC Fiber-Reinforced γ-TiAl Composites Prepared by Suction Casting

The process of preparing SiC fiber-reinforced y-TiAl composites by the conventional methods is difficult and complicated due to the high reactivity,high melting point and poor deformability of y-TiAl alloys.In this work,suction casting,a promising method for preparing SiC_f/TiAl composite,had been attempted.In the process,y-TiAl alloy melt was introduced rapidly into a mold within pre-arranged fibers that were coated with additional layer of titanium alloy.This simple method successfully prevented serious reactions between the alloy melt and the fibers which remained intact during the solidification process.The interfacial reaction layer was observed by optical microscopy,scanning electron microscopy(SEM).The interfacial reaction products were identified by transmission electron microscopy(TEM).Tensile tests of the matrix alloy and composites were performed at room temperature and 800 ℃.The results exhibited that the tensile strength of SiC_f/γ-TiAl composite was higher than that of the matrix alloy at both room temperature and 800 0 C.At room temperature,tensile strength of SiC_f/γ-TiAl composite was increased by about 7%(50 MPa),whereas a double increase in tensile strength 14%(100 MPa)was obtained at 800 ℃.The titanium alloy coating on the fiber not only prevented the serious interfacial reaction between the y-TiAl alloy melt and the SiC fiber,but also played a role in delaying the propagation of cracks in the matrix to the fiber at 800 ℃.The fracture mechanism of the composite was analyzed by fracture metallographic analysis.     

V微合金化对55SiCr钢组织和抗延迟断裂性能的影响

利用光学显微镜(OM)、扫描电镜(SEM)、热力学计算、物理化学相分析和恒载荷缺口拉伸试验,研究了V微合金化对55SiCr弹簧钢淬火和回火后的组织和抗延迟断裂性能的影响。结果表明,由于微合金化元素V的加入,试验钢经淬火和回火后的屈服强度提高了150 MPa,抗拉强度提高了100 MPa,同时获得了尺寸集中在18～36 nm的MC析出相,有效阻止了淬火保温时奥氏体晶粒的长大,将奥氏体晶粒尺寸由15.4μm细化至4.7μm。添加V元素后,在超细晶粒和MC型纳米析出相作为氢陷阱的共同作用下,55SiCr弹簧钢获得高强度和更好的抗延迟断裂性能。     

Effect of Yb addition on strength and fracture toughness of Al-Zn-Mg-Cu-Zr aluminum alloy

The effect of Yb addition on the strength and fracture toughness of Al-Zn-Mg-Cu-Zr aluminum alloy was investigated by measuring tensile properties and fracture toughness. The surface morphology was observed by optical microscopy, scanning electron microscopy and transmission electron microscopy. The results show that Yb addition can produce fine coherent Yb contained dispersoids. Those dispersoids trend to inhibit AI matrix recrystallization and retain the recovery deformed microstructure. Compared with Al-Zn-Mg-Cu-Zr alloy, Yb contained alloy demonstrates mechanical property improvements from 710 MPa to 747 MPa for ultimate strength, from 684 MPa to 725 MPa for yield strength, from 21 MPa·m1/2 to 29 MPa·m1/2 for fracture toughness with T6 treatment.     

Developing high performance squeeze cast Al-Cu alloys with high Fe and Cu contents

In this paper, the microstructural evolution and mechanical properties of squeeze cast Al-Cu alloys with different amounts of Cu and Fe after T7 heat treatment were investigated using various methods, including optical microstructure (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), electron probe micro-analyzer (EPMA), and tensile testing. Results show that better comprehensive mechanical properties of squeeze cast Al-Cu alloys can be achieved by designing the Fe and Cu contents. These results can be attibuted to an increase in precipitate particles in the α(Al) matrix and the formation of nano-sized iron-rich intermetallics (IRIs). Ultimate tensile strength (UTS), yield strength (YS), and elongation (EL) of the Al-6.5Cu-0.6Mn-1.0Fe alloy were as high as 314 MPa, 293 MPa, and 6 %, respectively. These values were close to those of Al-Si alloys with high Fe content (1.0 %) under applied pressure, and this indicates the high potential for developing recycled squeeze cast Al-Cu cast alloys.     

导电聚合物复合材料的产热特性及电阻焊接工艺

以丙烯腈-丁二烯-苯乙烯塑料(ABS)为基体,导电聚苯胺(PANI)和导电炭黑(CB)作为填充剂制备了导电聚合物基复合材料,测试分析了聚合物复合材料在不同焊接电压下焊接界面处温度随焊接时间的变化规律,并以其作为加热电阻研究了聚碳酸酯(PC)的电阻焊接工艺.结果表明,焊接电压和焊接时间对焊接效果的影响很大.选定较为合适的功率,在一定焊接时间内可以达到适合的焊接温度,接头的焊接界面处聚合物电阻片与母材有互融出现,形成了很好的接合,其接头强度达到了25.4MPa.探索了采用导电聚合物为产热器件进行塑料电阻焊接的新方法.     

封闭锻造挤压镁合金同步提高强度和塑性（英文）

介绍一种用于AZ31镁合金的新型连续塑性工艺,即闭式锻造挤压。采用光学显微镜、扫描电子显微镜、电子背散射衍射和拉伸和压缩试验研究合金微观结构的演变和强化机制。结果表明,该工艺可以促进动态再结晶,消除粗大的未动态再结晶晶粒区域,有效细化晶粒,并提高合金的强度、塑性和各向异性。晶粒细化主要归功于应力,促进再结晶的形核并细化组织。完全再结晶的超细晶组织同时提高了强度和塑性。经过60 s封闭锻造和连续挤压后,合金表现出较高的力学性能,其拉伸屈服强度、抗拉强度、抗压强度、伸长率和屈服不对称性分别为305 MPa、337 MPa、295 MPa、27%和0.97。     

形变热处理对Cu-Ag-Cr和Cu-Ag-Zr合金组织和性能的影响

采用中频熔炼-铁模铸造-热轧-固溶-冷轧-时效处理工艺,制备了Cu—Ag-Cr和Cu—Ag-Zr两种合金板材。通过拉伸力学性能测试、电导率测试、金相和透射电子显微镜观察,研究了固溶-预冷变形-时效对加入微量Cr、Zr的Cu—Ag合金组织和性能的影响。结果表明：在Cu—Ag合金中添加微量Cr和Zr,能显著地提高铜银合金的力学性能,添加Cr时,电导率有-定降低,而添加Zr时,电导率没有明显变化;两种合金较好的形变热处理工艺为时效前进行30％冷变形,然后在450℃下时效4h,在此工艺条件下Cu—Ag-Cr合金的抗拉强度、伸长率、相对电导率分别为397MPa、16．8％和78％IACS,Cu—Ag-Zr合金的抗拉强度、伸长率、相对电导率分别为373MPa、10％和96％IACS;形变热处理能够显著提高研究合金的力学性能而不明显降低电导率,微量Cr、Zr以Cr单质和Cu3Zr粒子的形式在基体中弥散析出,是合金强度提高的主要原因,而纯铜的基体仍使其具有较高的电导率。     

化学气相沉积高纯钨的择优取向与性能研究

利用光学显微镜、X射线衍射(XRD)和扫描电子显微镜的电子背散射衍射花样(electronic backscatter ring diffraction,EBSD),对用化学气相沉积制备的高纯钨进行了微观结构和晶面取向分析;利用霍普金森压杆系统和电子万能试验机测试了高纯钨的动态和准静态力学性能。研究表明：化学气相沉积高纯钨具有柱状晶组织,并且具有明显的(100)择优取向;动态屈服强度达到2000 MPa以上,静态屈服强度约为1350 MPa,具有应变速率敏感性     

Microstructure Evolution and Tensile Properties of Laser-TIG Hybrid Welds of Ti2AlNb-Based Titanium Aluminide

The microstructure of laser-tungsten inert gas hybrid welded Ti₂AlNb-based joints and their tensile properties at room temperature were investigated in this paper. The results showed that good-quality joints could be obtained by hybrid welding process. The microstructure evolution was identified by means of optical microscopy, scanning electron microscopy, x-ray diffraction, and transmission electron microscopy. The fusion zone mainly consisted of B2 phase due to the rapid cooling rate, as well as high Nb content. The phase compositions of the heat-affected zone were varied with different thermal cycles during the welding process. Tensile tests at room temperature showed that fracture tended to occur in the fusion zone, and the tensile strength and elongation were 950 MPa and 4.3%, respectively. The fracture mode was quasi-cleavage based on the observation of the fracture morphology.     

2195-T6铝锂合金搅拌摩擦焊接头微观组织结构与力学性能

采用冷源辅助搅拌摩擦焊对2 mm厚的HSn70-1锡黄铜进行对接焊接,并获得了无缺陷的焊接接头. 利用光学显微镜、电子背散射衍射、透射电子显微镜和拉伸试验,分析搅拌区的微观组织及其对强化机制和应变硬化行为的影响. 结果表明,干冰乙醇混合物的快速冷却作用不仅消除了热影响区,还抑制了搅拌区的位错回复和晶粒长大. 搅拌区呈现具有较高位错密度的超细晶结构,搅拌区的抗拉强度为486 MPa,比母材提高了53.8%,断后伸长率也达到了30%,搅拌区屈服强度较母材提高了47.1%,其强化机制主要为固溶强化和晶界强化,但搅拌区的应变硬化行为主要受晶粒尺寸和位错密度的影响. 由拉伸过程中产生的纳米尺度变形孪晶可协调塑性变形,并有效缓解应力集中,使搅拌区强度提高的同时仍具有良好的延展性.

     

Interfacial reaction product and mechanical properties of the electron beam brazed K465 Ni-based superalloy joints

Ni-based superalloy K465 is brazed with BNi-2 filler metal by vacuum electron beam brazing (VEBB). In process of VEBB, effects of processing primary parameters on shear strength of joints are investigated. Microstructure of the brazed joint with BNi-2 filler metal is studied by means of scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). The results show that the structure of brazed seam consists of a large amount of Ni-based γ solid solution, Ni3Al (γ′), Ni3B, WB, CrB, and a small quantity of WC, NbC. The maximum shear strength of the joint is 398 MPa when the beam current of welding is 2.6 mA, heating time is 480 s and focused current is 1 800 mA.     

超音速等离子喷涂工艺参数对AlSi20%Al/Ni涂层结合强度的影响

为使AlSi-20%Al/Ni超音速等离子喷涂涂层获得优良的结合性能,采用正交实验法研究了喷涂距离、喷涂电压、喷涂电流等喷涂工艺参数对结合强度的影响。利用X射线衍射、扫描电镜等手段对涂层的相组成和断口形貌进行分析,利用WDW-E100D微机控制式万能拉伸试验机对涂层结合强度进行测试。结果表明:涂层由AlSi和AlNi两相组成,影响AlSi-20%Al/Ni涂层结合强度工艺参数的主次顺序为喷涂距离、喷涂电压、喷涂电流,优化后的工艺参数为主气流量3.2m3/h,喷涂电流为380A,喷涂电压为130V,喷涂距离为90mm,在此参数下制备的涂层组织致密,其结合强度为65.5MPa。     

硼酸铝晶须增强铝基复合材料的显微组织、力学性能和磨损性能（英文）

通过传统的粉末冶金技术制备不同含量硼酸铝晶须(ABOw)(5%, 10%, 15%,质量分数)增强的商业纯铝基复合材料,并对其显微组织特征和力学性能进行研究。采用粉末冶金方法有效混合铝粉和ABOw,将混合粉冷压后在600℃下烧结。通过光学显微镜(OM)、扫描电子显微镜(SEM)、能谱分析(EDS)、透射电子显微镜(TEM)和X射线衍射(XRD)对烧结后的复合材料进行显微组织表征,测定复合材料的孔隙率随ABOw含量的变化,研究ABOw含量变化对复合材料的力学性能,包括硬度、抗弯强度和抗压强度的影响,及复合材料在恒定载荷下、不同滑动距离下的干滑动磨损行为。结果表明,当ABOw含量为10%(质量分数)时,复合材料具有最大的抗弯强度和抗压强度,分别为172 MPa和324 MPa,并且硬度得到改善,约为HV 40.2。但是,随着ABOw含量的进一步增加,性能降低。含10%ABOw复合材料的耐磨性能也得到显著提高。Al-10%ABOw复合材料优异的综合性能归因于其具有良好的界面结合性能、低的孔隙率和好的组织均匀性。     

On the Al5083–Al<Subscript>2</Subscript>O<Subscript>3</Subscript>–TiO<Subscript>2</Subscript> Hybrid Surface Nanocomposite Produced by Friction Stir Processing

In this study Al5083–Al₂O₃–TiO₂ hybrid surface nanocomposite was successfully prepared by friction stir processing (FSP). The effects of different combination of rotational and travel speed of tool were investigated. The samples were characterized by optical and scanning electron microscopy (SEM), microhardness and undergone tensile and wear tests. Based on the maximum tensile strength and hardness value, optimum rotational speed of 710 rpm and travel speed of 20 mm/min was achieved. The microhardness and tensile strength of the as-received alloy and specimens having optimum surface nanocomposite were about 80 Hv, 285 MPa, 140 Hv and 375 MPa, respectively. Surface nanocomposites showed significantly lower friction coefficients and wear rates than those obtained for substrate. Based on scanning electron microscopy tests, abrasive wear as dominant wear mechanism was detected.     

高温均匀化处理对1.3C-5Cr-0.7Mo-0.6V钢中碳化物形貌及力学性能的影响

为改善1.3C-5Cr-0.7Mo-0.6V钢中一次碳化物形貌,在1170 ℃下对其进行了不同时间的高温均匀化处理并水淬至室温,之后对其进行退火-淬火-回火处理。采用扫描电镜(SEM)、透射电镜(TEM)、X射线衍射仪(XRD)及压缩试验等方法对不同时间高温均匀化处理后样品的形貌、物相及力学性能进行分析。结果表明,高温均匀化处理可以有效改善一次碳化物的尺寸及形貌,由网状变为均匀分布的小球状。试验钢在高温均匀化处理3 h时取得了抗压强度4703 MPa、工程应变37.3%的压缩力学性能;较未均匀化处理的钢而言,其压缩强度和压缩应变分别提升 14.5%和30.8%。